In the prefabrication of a sheet metal wall module of the character to which the present invention pertains, a series of parallel studs with pairs of parallel longitudinal side flanges are telescoped at their upper ends into an upper horizontal cap member having a pair of parallel longitudinal dependent side flanges and at their lower ends into a lower horizontal floor cap member having a pair of parallel longitudinal upright side flanges. Thus, the side flanges of each stud are in intimate surface contact with the side flanges of the upper and lower horizontal members so that there are two rectangular areas of two layers of sheet metal at each juncture of a stud with a horizontal member. The metal studs normally simulate wooden 2.times.4 units, thus having webs about 35/8 inches wide and flanges about 13/8 inches wide. The studs are preferably of C-shape though they may be of other non-planar configuration. The cap members and track members also normally simulate 2.times.4 wooden members, thus also having webs with widths of about 35/8 inches and flanges having widths of about 11/4 inches. The cap and track members, however, are normally of U-shape.
Different expedients have been employed heretofore to join the longitudinal flanges of the studs to the longitudinal flanges of the two horizontal members at each juncture to result in an acceptably rigid wall module. For example, various fastener elements have been employed including sheet metal screws and blind rivets. In each instance, such a fastener element necessarily protrudes beyond the outer surface of a corresponding longitudinal flange of an upper or lower longitudinal member and to that extent interferes with the fastening of sheet material to finish a building wall. In addition, it is necessary to provide a supply of fastener elements and to take time to handle them.
There has been a pressing need for a sheet metal joint for use in a prefabricated metal sheet wall module that eliminates the need for using such fastening elements. This need might be achieved by utilizing a crimping system such as that disclosed in British Pat. No. 145,380 or U.S. Pat. No. 3,010,199, or U.S. Pat. No. 3,320,843. In fact, tools that have heretofore been on the market, have been employed to produce crimps like that shown in British Patent No. 145,380 at the junctures of studs and horizontal members of wall sections. Such operations, however, have been performed on site and as far as is known, have not been successfully applied to the prefabrication of wall section modules that are to be transported from a prefabrication station to the construction site.